Multi-function apparatus

ABSTRACT

A multi-function apparatus includes a body, an image reading unit, a document cover and a locking member. The image reading unit is movable between a closed position and an opened position. The document cover is movable between a closed position and an opened position. The locking member is movable to a first position and a second position and includes a first engagement portion and a second engagement portion. In response to a movement of the document cover to the opened position, the locking member moves to the first position and locks the image reading unit to the closed position. In response to a movement of the image reading unit to the opened position, the locking member moves to the second position and locks the document cover to the closed position.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.15/625,431, filed on Jun. 16, 2017; which is a continuation of U.S.patent application Ser. No. 15/269,338, filed on Sep. 19, 2016, now U.S.Pat. No. 9,692,920 B2, issued on Jun. 27, 2017; which is a continuationof U.S. patent application Ser. No. 14/942,970, filed on Nov. 16, 2015,now U.S. Pat. No. 9,451,107 B2, issued on Sep. 20, 2016; which is acontinuation of U.S. patent application Ser. No. 14/320,612, filed onJun. 30, 2014, now U.S. Pat. No. 9,191,533 B2, issued on Nov. 17, 2015;which is a continuation of U.S. patent application Ser. No. 14/108,303,filed on Dec. 16, 2013, now U.S. Pat. No. 8,767,231 B2, issued on Jul.1, 2014; which is a continuation of U.S. patent application Ser. No.12/890,414, filed on Sep. 24, 2010, now U.S. Pat. No. 8,610,910 B2,issued on Dec. 17, 2013; which claims the benefit of Japanese PatentApplication No. 2009-223484, which was filed on Sep. 28, 2009, theentire disclosures of each of which are incorporated herein by referencein their entirety.

BACKGROUND 1. Field of the Invention

The present invention relates to a multi-function apparatus having adocument cover, an image reading unit.

2. Description of the Related Art

A multi-function apparatus including a document cover and an imagereading unit is known. The multi-function apparatus includes a firstlocking member which locks the document cover to the image reading unit,and a second locking member which locks the image reading unit to theprinter housing. This configuration prevents the document cover and thescanner housing from opening simultaneously for the sake of security.

SUMMARY

Since the multi-function apparatus has two locking members, a lockingunit becomes larger in size and the apparatus also becomes larger insize. In addition, a locking mechanism in the lock unit comes to becomplicated.

A need has arisen to provide a multi-function apparatus having aspace-saving and safe locking mechanism that is formed with fewercomponents.

According to an embodiment of the present invention, a multi-functionapparatus includes a body, an image reading unit, a document cover and alocking member. The image reading unit has a document placing surfaceand is configured to read an image of a document placed on the documentplacing surface. The image reading unit is movable between a closedposition to cover an upper portion of the body and an opened position toopen the upper portion. The document cover is movable between a closedposition to cover the document placing surface and an opened position toopen the document placing surface. The locking member is movable to afirst position and a second position and includes a first engagementportion capable of engaging with the body and a second engagementportion capable of engaging with the document cover. When the lockingmember is in the first position, the first engagement portion preventsthe image reading unit from moving from the closed position to theopened position by engaging with the body. When the locking member is inthe second position, the second engagement portion prevents the documentcover from moving from the closed position to the opened position byengaging with the document cover. Furthermore, in response to a movementof the document cover to the opened position, the locking member movesto the first position and locks the image reading unit to the closedposition. In response to a movement of the image reading unit to theopened position, the locking member moves to the second position andlocks the document cover to the closed position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating the appearance of amultifunctional apparatus as an example according to an embodiment ofthe invention.

FIG. 2 schematically and separately illustrates a cross-sectionalstructure of a document cover taken along a line II-II in FIG. 1.

FIG. 3A schematically and separately illustrates a cross-sectionalstructure of a scanner housing taken along a line II-II in FIG. 1.

FIG. 3B schematically and separately illustrates a cross-sectionalstructure of the scanner housing taken along a line II-II in FIG. 1.

FIG. 4A schematically and separately illustrates a cross-sectionalstructure of a printer housing taken along a line II-II in FIG. 1.

FIG. 4B schematically and separately illustrates a cross-sectionalstructure of the printer housing taken along a line II-II in FIG. 1.

FIG. 5A is a cross-sectional view schematically illustrating a lockingmechanism under the operation in which the document cover is beingopened.

FIG. 5B is a cross-sectional view schematically illustrating the lockingmechanism under the operation in which the document cover is beingopened.

FIG. 6A is a cross-sectional view schematically illustrating the lockingmechanism under the operation in which the document cover is beingopened.

FIG. 6B is a cross-sectional view schematically illustrating the lockingmechanism under the operation in which the document cover is beingopened.

FIG. 7A is a cross-sectional view schematically illustrating the lockingmechanism under the operation in which the document cover is beingopened.

FIG. 7B is a cross-sectional view schematically illustrating the lockingmechanism under the operation n which the document cover is beingopened.

FIG. 8 is a cross-sectional view schematically illustrating the documentcover being in a fully open state.

FIG. 9A is a cross-sectional view schematically illustrating the lockingmechanism under the operation in which a scanner housing is beingopened.

FIG. 9B is a cross-sectional view schematically illustrating the lockingmechanism under the operation in which the scanner housing is beingopened.

FIG. 10A is a cross-sectional view schematically illustrating thelocking mechanism under the operation in which the scanner housing isbeing opened.

FIG. 10B is a cross-sectional view schematically illustrating thelocking mechanism under the operation in which the scanner housing isbeing opened.

FIG. 11A is a cross-sectional view schematically illustrating thelocking mechanism under the operation in which the scanner housing isbeing opened.

FIG. 11B is a cross-sectional view schematically illustrating thelocking mechanism under the operation in which the scanner housing isbeing opened.

FIG. 12 is a cross-sectional view schematically illustrating the scannerhousing being in a fully open state.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the invention will be hereinafter described withappropriate reference to the accompanying drawings. The embodimentsdescribed below are merely examples of the invention, and obviously, theembodiments can be suitably modified without departing from the scope ofthe invention.

FIG. 1 is a perspective view illustrating the appearance of amultifunctional apparatus 10 according to an embodiment of theinvention. In the following description, a vertical direction 7 isdefined on the basis of a state in which the multifunctional apparatus10 is installed so as to be able to be used (state in FIG. 1), and alongitudinal direction 8 is defined on the basis that a side on which anopening 13 is formed is a foreside (front side), and a lateral direction9 is defined on the basis of viewing the apparatus 10 from the foreside(front side).

The multifunctional apparatus 10 is an example of the multi-functionapparatus. As illustrated in FIG. 1, the multifunctional apparatus 10 isgenerally formed in a thin rectangular-parallelepiped shape in which awidth (length in the lateral direction 9) and a depth (length in thelongitudinal direction 8) are larger than a height (length in thevertical direction 7). The multifunctional apparatus 10 has variousfunctions including a facsimile function, a printer function, a scannerfunction, and a copy function. The multi-function apparatus is notlimited to one having all of the above functions and, for example, maybe applied to a multifunctional apparatus having only the printerfunction and the scanner function or to a copier having only the copyfunction. Furthermore, the multi-function apparatus may be applied to amultifunctional apparatus having some function besides the printerfunction.

An ink jet printer 11 is disposed in a lower portion of themultifunctional apparatus 10. The printer 11 has a printer housing 14(an example of a body) which is provided with the opening 13 in thefront side thereof. A tray 24 is disposed in the opening 13 and servesto accommodate recording paper. The printer 11 is not limited to an inkjet type of printer, and an electrophotographic printing technique or athermal transfer printing technique may be employed.

The scanner 12 is disposed on the printer 11. The scanner 12 has ascanner housing 15 (an example of an image reading unit) which isprovided with contact glass (not illustrated) on an upper surfacethereof. A document having an image to be scanned is placed on an uppersurface of the contact glass (corresponding to a document placingsurface).

The scanner housing 15 is supported by a supporting mechanism, such as ahinge, on the back side of the multifunctional apparatus 10 so as to beopenable and closeable with respect to an upper surface of the printerhousing 14. By virtue of this configuration, the scanner housing 15 iscapable of being rotated between a closed position in which the scannerhousing 15 covers the upper portion of the printer housing 14 (positionillustrated in FIGS. 1, 5A, and 5B) and an opened position in which thescanner housing 15 is moved away from the upper portion of the printerhousing 14 in the upward direction (position illustrated in FIGS. 11A,11B, and 12). In the embodiment, the upper portion of the printerhousing 14 is in an open state. Therefore, in cases where the scannerhousing 15 is lifted to reveal the upper portion of the printer housing14 as illustrated in FIG. 12, users are capable of accessing the insideof the apparatus from the upper portion of the printer housing 14.Consequently, users are capable of performing maintenance of componentsin the printer 11 and removing paper jam. As described above, thescanner housing 15 serves as a cover that covers the upper portion ofthe printer housing 14.

The scanner 12 includes a document cover 17 (an example of a documentcover) that covers a document placed on the contact glass. The documentcover 17 is supported by a supporting mechanism, such as a hinge, on aback side of the multifunctional apparatus 10 so as to be able to beopenable and closeable with respect to the contact glass disposed on theupper surface of the scanner housing 15. By virtue of thisconfiguration, the document cover 17 is capable of being rotated betweena closed position in which the document cover 17 covers the uppersurface of the contact glass (position illustrated in FIGS. 1, 5A, and5B) and an opened position in which the document cover 17 is moved awayfrom the upper surface of the contact glass in the upward direction(position illustrated in FIGS. 7A, 7B, and 8).

The document cover 19 includes an auto document feeder (ADF) 19. The ADF19 picks up a plurality of documents placed at a predetermined positionone at a time, transports the documents through a scanning position onthe contact glass, and then ejects the documents to a document ejectionsection 22.

The multifunctional apparatus 10 includes a locking mechanism 50. Thelocking mechanism 50 is disposed at a front portion in themultifunctional apparatus 10. The locking mechanism 50 has a functionwith which the scanner housing 15 is engaged with the printer housing 14to be locked thereto and has a function with which the scanner housing15 is engaged with the document cover 17 to be locked thereto.

[Locking Mechanism 50]

With reference to FIGS. 2A to 4B, the locking mechanism 50 includes arotating body 52 (an example of a locking member) and a pair ofsupporting sections 53 and 54 (an example of a supporting portion, seeFIG. 3B). FIG. 2 is a cross-sectional view schematically illustratingthe document cover 17. FIG. 3A is a cross-sectional view schematicallyillustrating the scanner housing 15. FIG. 3B is a cross-sectional viewschematically illustrating the scanner housing 15 taken along a lineIIC-IIC in FIG. 3A. FIG. 4A is a cross-sectional view schematicallyillustrating the printer housing 14. FIG. 4B is a cross-sectional viewschematically illustrating the printer housing 14 taken along a lineIIE-IIE in FIG. 4A. In FIGS. 3A and 3B, for the purpose of simplifyingthe description, a shaft 65 is illustrated so as to be positioned at theleading end of a slot 57.

The supporting sections 53 and 54 are disposed inside the scannerhousing 15. The supporting sections 53 and 54 are vertically disposed ona lower wall 15A of the scanner housing 15. With reference to FIG. 3B,the supporting sections 53 and 54 are disposed so as to be spaced atpredetermined intervals in the lateral direction 9. The supportingsection 53 includes a supporting portion 58 having the slot 57 extendingin the vertical direction 7 and penetrating in the lateral direction 9and includes an arch-shaped leg 60 extending toward the lower wall 15Afrom both sides of the supporting portion 58 in the longitudinaldirection 8. Because the supporting section 54 has a configuration thesame as that of the supporting section 53, components of the supportingsection 54 are denoted by the same numbers assigned to correspondingcomponents of the supporting section 53, and therefore description ofthe section 54 is omitted.

The rotating body 52 includes the shaft 65 (an example of a shaft), afirst arm 67 (an example of a first arm portion), a second arm 71 (anexample of a second arm portion), and a third arm 75 (an example of athird arm portion), these arms extending from the center of the shaft 65in a direction perpendicular to the shaft 65. The rotating body 52 isdisposed between the supporting sections 53 and 54. The shaft 65 of therotating body 52 is supported by the supporting portion 58 of each ofthe supporting sections 53 and 54. Specifically, the shaft 65 isinserted into the slot 57 of the supporting portion 58. The shaft 65extends through the slot 57, and one end 65A of the shaft 65 protrudesleftward from the supporting section 53, and another end 65B of theshaft 65 protrudes rightward from the supporting section 54 (see, FIG.3B).

The shaft 65 has a cross-sectional surface formed in a substantiallyoval shape. Specifically, a circumferential surface of a round bar ispartially cut into a planar shape to produce the shaft 65 having a pairof parallel surfaces on the circumferential surface. Accordingly, thecross sectional surface of the shaft 65 has a larger width and a smallerwidth. A round groove 57A (an example of a round hole) is formed on theupper end of the slot 57. An inside diameter of the round groove 57A isconfigured so as to be larger than the larger width of the crosssectional surface of the shaft 65, so that the shaft 65 is rotatablysupported by the round groove 57A. The slot 57 includes the round groove57A and a narrow portion 57B extending from the round groove 57A to thelower end of the slot 57. The narrow portion 57B (an example of a oblonghole) is formed so as to have a width narrower than the inside diameterof the round groove 57A, and specifically the narrow portion 57B has awidth narrower than the larger width of the cross sectional surface ofthe shaft 65 but wider than the smaller width thereof.

Because the shaft 65 and the slot 57 are formed as described above, thesupporting portion 58 enables the rotating body 52 to be rotated aboutthe shaft 65 when the shaft 65 is positioned in the round groove 57A asindicated by an unbroken line in FIG. 3A. In cases where the rotatingbody 52 is in a reference position (corresponding to a referenceposition) indicated by the unbroken line in FIG. 3A, the shaft 65 iscapable of sliding in the slot 57 in the vertical direction 7. Namely,in the shaft 65 of the rotating body 52, a portion supported by the slot57 is formed in a shape which enables the shaft 65 to move from theround groove 57A to the narrow portion 57B when the rotating body 52 isin the reference position. Because the width of the narrow portion 57Bis smaller than the larger width of the cross sectional surface of theshaft 65, the shaft 65 that has entered the narrow portion 57B isincapable of being rotated. Namely, in a state in which the shaft 65 ispositioned in the narrow portion 57B, the rotation of the rotating body52 to a first position (described hereinafter and corresponding to afirst position) is restricted (prohibited), and the reference positionis therefore held. In other words, in the shaft 65 of the rotating body52, a portion to be supported by the slot 57 is formed in a shape whichenables positional change to the first position to be restricted whenthe shaft 65 has entered the narrow portion 57B. In cases where theshaft 65 is positioned in the round groove 57A and where the rotatingbody 52 is in the first position, the shift of the shaft 65 from theround groove 57A to the narrow portion 57B is restricted (prohibited).

The term “reference position” means a state in which the rotating body52 is not engaged with any of the document cover 17 and the printerhousing 14 and means a state in which the shaft 65 is positioned in theround groove 57A and in which a second arm 71 vertically extends upwardfrom the shaft 65. The shaft 65 is formed such that the larger width ofthe cross sectional surface thereof is aligned with a longitudinaldirection of the slot 57 in cases where the rotating body 52 is in thereference position. Accordingly, in cases where the rotating body 52 isin the reference position, the shaft 65 is capable of entering thenarrow portion 57B, and therefore the rotating body 52 is capable ofsliding in the vertical direction 7 within the narrow portion 57B.Furthermore, because each of the shaft 65 and the slot 57 is formed soas to have the size described above, the shaft 65 that has entered thenarrow portion 57B is incapable of being rotated.

The slot 57 extends in a vertical direction. In cases where an externalforce is not applied to the rotating body 52, the rotating body 52 isexposed to a downward force F2 from its own weight. Accordingly, incases where the shaft 65 enters the narrow portion 57B in such a state,the rotating body 52 begins to move downward along the narrow portion57B. Then, the shaft 65 reaches the lower end of the narrow portion 57B,and the rotating body 52 takes a second position (corresponding to asecond position) indicated by a dashed line in FIG. 3A. The rotatingbody 52 may be biased downward from the reference position not only byits own weight but by using a biasing member such as a spring.

A first hook 68 (an example of a first hook) that is engaged with theprinter housing 14 is formed at the leading end of the first arm 67. Thefirst hook 68 is configured so as to be able to be engaged with anengagement member 34 formed on the printer housing 14. The first arm 67and the first hook 68 form a first engagement portion. An opening 80into which the first arm 67 and the first hook 68 are capable of beinginserted is formed on the lower wall 15A of the scanner housing 15. Anopening (not illustrated) into which the first arm 67 and the first hook68 are capable of being inserted is formed on the upper wall 14B of theprinter housing 14. The first arm 67 and the first hook 68 protrudedownward from the opening 80. The engagement member 34 is disposed onthe upper wall 14B of the printer housing 14 and protrudes downward fromthe upper wall 14B. In the embodiment, in cases where the scannerhousing 15 is in the closed position and where the rotating body 52 isin the first position described hereinafter, the first hook 68 that hasentered the printer housing 14 from the opening on the upper wall 14B isengaged with the engagement member 34 to lock the scanner housing 15 tothe printer housing 14 in the vertical direction 7. The first hook 68and the engagement member 34 may appropriately employ any configurationin so far as they are capable of engaging with each other.

A second hook 72 (an example of a second hook) is formed at the leadingend of the second arm 71. The second arm 71 and the second hook 72 forma second engagement portion. The second hook 72 is configured to beengaged with the document cover 17. Specifically, the second hook 72 isformed so as to be able to be engaged with an engagement arm 36 (anexample of an engagement arm) disposed on the document cover 17. Theengagement arm 36 includes an arm 37 extending downward from a lowerwall 17A of the document cover 17 in an oblique direction toward thefront side and includes a hook 38 extending backward from the vicinityof the leading end of the arm 37 in a horizontal direction. An opening81 (see, FIG. 3B) is formed in the upper wall 15B of the scanner housing15 at a position corresponding to the engagement arm 36. During aprocess in which the document cover 17 shifts from the opened positionto the closed position to cover the upper surface of the scanner housing15, the leading end 39 and the hook 38 of the engagement arm 36 enterthe scanner housing 15 through the opening 81. The second hook 72 isconfigured so as to be able to be engaged with the hook 38 that hasentered the scanner housing 15. In the embodiment, in cases where therotating body 52 is in the second position (position indicated by adashed line in FIG. 3A), the second hook 72 is engaged with theengagement arm 36, so that the scanner housing 15 is locked to thedocument cover 17. The second hook 72 and the engagement arm 36 mayappropriately employ any configuration in so far as they are capable ofengaging with each other.

With reference to FIG. 4A, a pair of supporting members 86 (an exampleof a second return mechanism, a bearing) are formed on the printerhousing 14. The supporting members 86 protrude upward from the upperwall 14B of the printer housing 14. Openings 88 (see, FIG. 3B) areformed on the lower wall 15A of the scanner housing 15 at positionscorresponding to the two ends of the shaft 65. In cases where thescanner housing 15 is in the opened position, the rotating body 52 is inthe second position. During a process in which the scanner housing 15shifts from the opened position to the closed position to cover theupper surface of the printer housing 14, the supporting members 86 enterthe scanner housing 15 through the openings 88, and then the upper ends87 of the supporting members 86 push up the two ends of the shaft 65against the downward force F2 (see, FIGS. 5A and 5B). Then, in caseswhere the scanner housing 15 is in the closed position, the upper ends87 help the shaft 65 to be positioned at the round groove 57A of theslot 57, so that the rotating body 52 is held in the reference position.

In the embodiment, in cases where the rotating body 52 is in thereference position indicated by the unbroken line in FIG. 3A, the secondarm 71 vertically extends upward, and the first arm 68 extends in adirection in which the first arm 68 is tilted backward at an angle θwith respect to a vertical direction. Weight balancing or the like isconfigured in each of the first arm 68, the second arm 71, and the thirdarm 75 such that the rotating body 52 is rotated in the anticlockwisedirection in FIG. 3A by being exposed to force F1 when force other thanthe gravity does not act on the rotating body 52. Conditions forrotating the rotating body 52 in the anticlockwise direction by exposingthe rotating body 52 to the force F1 in this manner (a length, shape,weight, and mounting angle in each of the arms) are appropriatelyconfigured depending on each component of the locking mechanism 50. Therotating body 52 may be biased in the anticlockwise direction from thereference position not only by its own weight but by using a biasingmember such as a spring.

The third arm 75 extends forward from the shaft 65 in a horizontaldirection while the rotating body 52 is in the reference state. In caseswhere the document cover 17 is in the opened position, the rotating body52 is exposed to the force F1 with the result that the rotating body 52is rotated in the anticlockwise direction to take a first positionillustrated in FIG. 7. During a process in which the document cover 17shifts from the opened position to the closed position to cover theupper surface of the scanner housing 15, the leading end 39 of theengagement arm 36, which has entered the scanner housing 15, downwardpresses the third arm 75. The leading end 39 downward presses the thirdarm 75, and then the rotating body 52 counteracts the force F1 in theanticlockwise direction, and thereby being rotated in a clockwisedirection. Then, the document cover 17 is in the closed position, therotating body 52 returns to the reference position, and thereby holdingthe reference position. In the embodiment, the third arm 75 and theleading end 39 of the engagement arm 36 form a first return mechanism.

[Opening and Closing Operation of the Document Cover 17 and Operation ofthe Locking Mechanism 50]

The opening and closing operations of the document cover 17 and theoperation of the locking mechanism 50 associated therewith will behereinafter described with reference to FIGS. 5A to 8.

FIGS. 5A and 5B illustrate the scanner housing 15 and the document cover17, both being in the closed position. In this case, the shaft 65 of therotating body 52 is held by the supporting members 86 at the roundgroove 57A, and therefore the rotating body 52 is not engaged with anyof the printer housing 14 and the document cover 17 to take thereference position. Namely, as illustrated in FIG. 5B, in the referenceposition, the first hook 68 of the first arm 67 is not engaged with theengagement member 34, and the second hook 72 of the second arm 71 is notalso engaged with the hook 38 of the engagement arm 36. As illustratedin FIG. 5B, in the reference position of the rotating body 52, thesecond hook 72 and the hook 38 overlap with each other in thelongitudinal direction 8 in a plan view but are spaced apart from eachother in the vertical direction 7 as viewed from a lateral side.

With reference to FIGS. 6A and 6B, in cases where the document cover 17is raised to be rotated from the closed position to the opened position,the engagement arm 36 also moves upward. In this case, because the thirdarm 75 is released from being pressed downward by the engagement arm 36,the rotating body 52 is rotated in the anticlockwise direction by theaction of the force F1 (see, FIG. 3A). The upward movement of theengagement arm 36 leads to the hook 38 approaching the second hook 72,whereas at the same time the second hook 72 moves away backward due tothe rotation of the rotating body 52 in the anticlockwise direction.Accordingly, in cases where the document cover 17 is rotated to theopened position, the second hook 72 is not engaged with the hook 38. Inother words, during a process in which the document cover 17 shifts tothe opened position, the second hook 72 and the hook 38 maintain a statein which they are not engaged with each other (engagement releasedstate), and accordingly the document cover 17 and the scanner housing 15maintain an unlocked state.

In cases where the document cover 17 is further raised as illustrated inFIGS. 7A and 7B, the rotating body 52 is further rotated in theanticlockwise direction. In this rotational process, the first hook 68of the first arm 67 is engaged with the engagement member 34 (see, FIG.7B). In cases where the first hook 68 is engaged with the engagementmember 34, the first arm 67 abuts on the engagement member 34, so thatthe rotation of the rotating body 52 stops. A position of the rotatingbody 52 at this time is the first position. In other words, in the firstposition, the first hook 68 is engaged with the engagement member 34,and the second hook 72 and the hook 38 maintain the engagement releasedstate. In the embodiment, because the rotating body 52 is exposed to theforce F1 in the anticlockwise direction, the rotating body 52 is held inthe first position.

Because the locking mechanism 50 acts as described above, the scannerhousing 15 is locked to the printer housing 14 even if the documentcover 17 is fully opened backward as illustrated in FIG. 8, so that thescanner housing 15 does not open while the document cover 17 is open.Namely, the document cover 17 and the scanner housing 15 do not open atthe same time.

Opening and Closing Operations of the Scanner Housing 15 and Operationof the Locking Mechanism 50

The opening and closing operations of the scanner housing 15 and theoperation of the locking mechanism 50 associated therewith will behereinafter described with reference to FIGS. 9A to 12.

In cases where the scanner housing 15 is raised to be rotated from theclosed position to the opened position in a state in which both of thescanner housing 15 and the document cover 17 are in the closed positionas illustrated in FIGS. 5A and 5B, the scanner housing 15 is spacedapart from the printer housing 14 as illustrated in FIGS. 9A and 9B.Accordingly, the round groove 57A gradually moves away upward from theleading end 87 of the supporting member 86. In this case, because therotating body 52 is exposed to the downward force F2 from its ownweight, the shaft 65 begins to move from the round groove 57A of theslot 57 to the narrow portion 57B. Namely, the rotating body 52relatively moves downward with respect to the scanner housing 15. Incases where the rotating body 52 moves downward, because the third arm75 moves away from the leading end 39 of the arm 36, the third arm 75 isreleased from being pressed by the leading end 39. Although the rotatingbody 52 is exposed to the force F1, the shaft 65 which has a crosssectional configuration formed in a substantially oval shape enters thenarrow portion 57B as described above, so that the rotation in theanticlockwise direction is restricted. In other words, the shaft 65 andthe narrow portion 57B restrict the rotation of the rotating body 52 inthe anticlockwise direction. Accordingly, in cases where the scannerhousing 15 is rotated to the opened position, the first hook 68 is notengaged with the engagement member 34. Namely, during a process in whichthe scanner housing 15 shifts to the opened position, the first hook 68and the engagement member 34 maintain a state in which they are notengaged with each other (engagement released state), and accordingly thescanner housing 15 and the printer housing 14 maintain an unlockedstate. In order that the shaft 65 smoothly moves from the round groove57A to the narrow portion 57B, each component may be designed such thatthe force F1 comes to be larger than the force F2.

With reference to FIGS. 10A and 10B, the rotating body 52 movesdownward, and then the second hook 72 approaches the hook 38. Then, withreference to FIGS. 11A and 11B, in cases where the slot 57 completelydeparts from the supporting member 86 and where the shaft 65 is thensupported at the lower end of the narrow portion 57B, the second hook 72is engaged with the hook 38. A position in which the second hook 72 isengaged with the hook 38 in this manner is the second position. In otherwords, in the second position, the second hook 72 is engaged with thehook 38, and the first hook 68 and the engagement member 34 maintain theengagement released state.

Because the locking mechanism 50 acts as described above, the documentcover 17 is locked to the scanner housing 15 even if the scanner housing15 is fully opened backward as illustrated in FIG. 12, so that thedocument cover 17 does not open while the scanner housing 15 is open.Namely, the document cover 17 and the scanner housing 15 do not open atthe same time.

In the embodiment, the third arm and the engagement arm are used as thefirst return mechanism, but, alternatively, an arm may be provided onthe document cover to directly press the second arm.

Furthermore, in the embodiment, the supporting member is used as asecond return mechanism, but, alternatively, a protrusion may beprovided on the first arm or the second arm such that the rotating bodymay be pushed up by contacting the protrusion.

Furthermore, in the embodiment, the printer housing is disposed on apart of the body, but, alternatively, another housing having otherfunction may be disposed in place of the printer housing.

Effects and Advantages of the Embodiments

As described above, in the embodiment, each of the document cover 17 andthe scanner housing 15 is incapable of separately taking the openedposition at the same time by virtue of the locking mechanism 50. Inother words, in cases where any one of the document cover 17 and thescanner housing 15 is in the opened position, the other is locked in theclosed position. In the related art, the document cover 17 and thescanner housing 15 simultaneously open to cause the multifunctionalapparatus 10 to fall, leading to damages or breakdowns of the apparatus10, but such problems are overcome. Accordingly, the safety of themultifunctional apparatus 10 is capable of being increased. Furthermore,the locking mechanism 50 of the embodiment is achieved by the onerotating body 52, leading to reduced number of components. Consequently,the locking mechanism 50 is capable of being formed in a smaller size,attributing the downsizing of the multifunctional apparatus 10.

What is claimed is:
 1. A multi-function apparatus comprising: a body; animage reading unit which has a document placing surface and which isconfigured to read an image of a document placed on the document placingsurface, the image reading unit being movable between a closed positionto cover an upper portion of the body and an opened position to open theupper portion, the image reading unit including a housing provided witha slot; a document cover movable between a closed position to cover thedocument placing surface and an opened position to open the documentplacing surface; a first engagement portion configured to engage withthe body, the first engagement portion having a first arm and a firsthook, the first hook extending from an end of the first armsubstantially perpendicularly; and a second engagement portionconfigured to engage with the document cover, the second engagementportion having a second arm and a second hook, the second hook extendingfrom an end of the second arm substantially perpendicularly and beingfolded at a distal end of the second hook and extending substantiallyparallel to the second arm, the second engagement portion including ashaft configured to be positioned in the slot, the second engagementportion being movable upward and downward when the shaft is positionedin the slot, wherein when the document cover is located in the openedposition, the shaft is positioned in an upper portion of the slot andthe first engagement portion engages with the body and locks the imagereading unit to the closed position, and when the image reading unit islocated in the opened position, the shaft is positioned in a lowerportion of the slot and the second engagement portion engages with thedocument cover and locks the document cover to the closed position. 2.The multi-function apparatus according to claim 1, wherein when theimage reading unit is located in the opened position, the shaft contactsa lower end of the slot.
 3. The multi-function apparatus according toclaim 2, wherein when the document cover is located in the openedposition, the shaft contacts an upper end of the slot.
 4. Themulti-function apparatus according to claim 1, wherein the firstengagement portion is configured to move in conjunction with movement ofthe second engagement portion.
 5. The multi-function apparatus accordingto claim 4, wherein the first engagement portion and the secondengagement portion are integrally formed.
 6. The multi-functionapparatus according to claim 1, wherein the slot includes an elongatehole and a circular hole connecting to the elongate hole, a width of theelongate hole in a horizontal direction being less than a width of thecircular hole in the horizontal direction.
 7. The multi-functionapparatus according to claim 6, wherein the circular hole is positionedin an upper end of the slot.
 8. The multi-function apparatus accordingto claim 6, wherein when the document cover is located in the openedposition, the shaft is pivotable in the circular hole.
 9. Themulti-function apparatus according to claim 1, wherein the firstengagement portion and the second engagement portion are relativelyfixed.
 10. The multi-function apparatus according to claim 1, whereinwhen both of the document cover and the image reading unit are locatedin the closed position, both of the first engagement portion and thesecond engagement portion are disengaged.
 11. The multi-functionapparatus according to claim 6, wherein the elongate hole extendsvertically.